title: Synthesis of densely functionalised 5-halogen-1,3-oxazin-2-ones by halogen-mediated regioselective cyclisation of N-Cbz-protected propargylic amines: a combined experimental and theoretical study.
abstract: A very efficient synthesis of 5-halogen-1,3-oxazin-2-ones has been accomplished by the halocyclisation reaction of chiral nonracemic N-carbobenzyloxy (N-Cbz)-protected propargylic amines by using I2, Br2 and Cl2 as electrophile sources. The nature of the halogen influences the reaction time and yield. However, in all cases the reaction is totally regioselective taking place through a 6-endo-dig process regardless of the nature of the halogen and of the substituents in the starting material. To rationalise the experimental results, theoretical studies at the B3LYP/6-311G* level have been performed.
authors.affiliation: Department de Química Orgànica-Facultat de Química, Universitat de València, C/Dr. Moliner 50, 46100 Burjassot (València) (Spain), Fax: (+34)963544328.
authors.forename: Alicia
authors.initials: A
authors.lastname: Monleón
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Blay
authors.forename: Luis R
authors.initials: LR
authors.lastname: Domingo
authors.forename: M Carmen
authors.initials: MC
authors.lastname: Muñoz
authors.forename: José R
authors.initials: JR
authors.lastname: Pedro
keywords: density functional calculations; halocyclisation; oxazinones; propargylic amines; reaction mechanisms; regioselectivity